Would you marry if it was only to ensure someone else's happiness?

Yes, yet another very vague question from yours truly! Perhaps the “someone” is so deeply in love with your new partner that they are experiencing detrimental health effects and marriage is “for some reason” the only way to convince him or her that they will never love them back. Yes, a ridiculous example, I know. But I’m sure you can think up a better one, so get answering!